This is a new core designed to analyze and quantify the nucleotide and nucleoside content of cell-tissue samples derived from in vitro and in vivo studies in Projects I-IV. These measurements will provide the analytical basis for assessing the "purinergic" component of the adaptive responses of the airways to environmental changes. This Core has evolved from the work during the current Program Project cycle, which has provided pioneering methodology for quantifying uridine nucleotides and introduced novel techniques, and adapted and modified published techniques for quantifying purine nucleotides. Major equipment maintained within the Core include two computerized high performance liquid chromatography (HPLC) unites supplied with automated sampler injectors, delivery systems (pumps), and fully range UV-light, spectrofluorometric, and radiomatic- and flow scintillation-detectors, and an auto-luminometer with injection capability for up to 180 samples. A detailed list of this equipment is provided on this Resources page. The laboratory is staffed with a trained, well-qualified technician who will provide samples for HPLC and luminometric analyses and will be responsible for the function and performance of the HPLC units.